attached to muscles innervated by the facial nerve orbicularis oris muscle mentalis muscle UBERON_0008596 A muscle of facial expression, innervated by the facial nerve, attached to the skin of the lower lip and inferior to the lower lip (in humans this region is called the chin or mental region), the orbicularis oris muscle, and the mandible in the symphyseal region. See Diogo et al., 2009; Burrows et al., 2011) symphyseal region lower lip